Schedule II - Condensed Financial Information of Registrant, Parenthetical (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Balance Sheets [Abstract]
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	20,000,000	20,000,000
Common stock, shares issued (in shares)	13,562,980	13,306,027
Common stock, shares outstanding (in shares)	13,562,980	13,306,027
Condensed Statements of Income [Abstract]
Operating expense, affiliated	$ 1,570	$ 1,356	$ 2,097
Condensed Statements of Cash Flows [Abstract]
Dividends paid to stockholders, affiliated	(7,377)	(6,749)	(6,357)
Parent company [Member]
Condensed Balance Sheets [Abstract]
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	20,000,000	20,000,000
Common stock, shares issued (in shares)	13,562,980	13,306,027
Common stock, shares outstanding (in shares)	13,562,980	13,306,027
Condensed Statements of Income [Abstract]
Operating expense, affiliated	777	605	584
Condensed Statements of Cash Flows [Abstract]
Dividends paid to stockholders, affiliated	$ (7,377)	$ (6,749)	$ (6,357)